The copying and redistribution of commercial imagery, audio and video productions has long been a cause of lost revenues to the creators/producers of such material. The advance of technology has not only expanded the means of legitimate distribution for audio and visual/video works, but has also made it easier to copy these materials for unauthorized purposes. In addition, there is a need to monitor, verify and track broadcasts and other distributions of this content.
Various methods have been developed to eliminate or limit both sophisticated and unsophisticated illegitimate distribution as well as to monitor distribution. Some of these methods rely on physical means. Others employ an auxiliary embedded signal to control, monitor and track usage of the content.
In accordance with preferred embodiments, a multi-bit auxiliary message (sometimes termed a “digital watermark”) is robustly embedded directly into the audio signal. Hardware or software systems can then read this message and, for example, and control, monitor or track usage of the content.
Key practical issues are addressed whereby the perceptual impact of this added message can be adjusted—both overall and as a function of the underlying audio content. In addition, robustness to various forms of distortion are addressed in a manner superior to the prior art.
Additionally, there are a variety of methods for detecting embedded data, and enhancements for improving detection, even where the signal has been subjected to distortion or is a compressed signal.
One combination includes a method comprising: obtaining a plural-bit identifier; obtaining a signal representing video data; cyclically applying the plural-bit identifier to the signal representing video data at the time of or as part of distribution of the video data, the plural-bit identifier being steganographically applied to the signal representing video data. The act of applying utilizes one or more pre-computed carrier signals.
Another combination includes a method comprising: obtaining video; processing data representing at least some portions of the video to hide a plural-bit payload therein, the plural-bit payload comprising at least a first portion and a second portion, the first portion representing public information, and the second portion representing private information.
Yet another combination includes a method comprising: determining features associated with video content; using the features or information derived from the features to adjust a watermark component; steganographically embedding the adjusted watermark component in the video content.
Still another combination includes a method comprising: determining features associated with video content; dynamically adjusting a watermark component based on at least the features; and steganographically embedding the adjusted watermark component in the video content.
Another combination includes a method comprising: obtaining a media signal comprising a message steganographically embedded therein; obtaining information from the media signal; adjusting a message detection process with reference to the information; detecting the message from the media signal according to the adjusted message detection process.
Yet another method of hiding a plural-bit message in a video signal includes: obtaining data representing elements of a video signal; altering a first set of the elements in accordance with a first bit of the message; altering a second set of the elements in accordance with a second bit of the message.
Still another combination includes a method of hiding at least a watermark element in a video signal comprising: obtaining data representing elements of a video signal; altering a first set of the elements in accordance with the watermark element. At least some of the first set of elements receive different amounts of altering relative to one another to hide the watermark element in the video signal.
Another combination recites a method comprising: obtaining a media signal; steganographically hiding information in data representing the media signal, wherein the information comprises at least device independent instructions; providing the media signal with the information steganographically hidden therein.
Still another combination provides a method comprising: obtaining first data representing an electronic or physical object; transmitting at least a portion of the first data to a remote server; receiving, from the server, data indicating which information from the electronic or physical object should be evaluated; evaluating indicated information; transmitting a result of said act of evaluating to the server; receiving, from the server, an indication concerning the result.
There are a variety of alternatives and enhancements to the above combinations.